It is generally known that polymeric materials have to be pretreated, for example by etching of the polymer surface with chromic/sulphuric acids, before chemical metallisation. However, this process can be applied only to those polymers, the surface of which can be modified oxidatively with the formation of caverns and vacuoles.
It is furthermore known that working with chromic/sulphuric acid, SO.sub.3 vapour or other oxidising agents is accompanied by a deterioration in the physical properties, such as the notched impact strength and the electrical surface resistance, of the polymeric material. Moreover, traces of hexavalent chromium, which rapidly lead to poisoning of the metal baths, often cause interference.
The known processes for the currentless metallisation of materials moreover comprise several process stages and have the disadvantage that they cannot be applied directly to all polymers. Chemical or physical roughening often has to be carried out.
It has therefore already been proposed to activate the polymer surfaces very gently using organometallic catalysts (compare, for example, U.S. Pat. No. 3,560,257 and EP-A 81,129). Nevertheless, this method, which is very elegant per se, is likewise not universally applicable. The use of solvents furthermore often leads to stress corrosion cracking being caused in the polymer injection moulding which is under tensile or compressive stress.
Other processes, such as are described in U.S. Pat Nos. 3,560,257 and 4,017,265 as well as DE-A 3,627,256, have the disadvantage that they require relatively larger quantities of expensive noble metal activators.